It’s the second week of the school year, and middle school librarian Kristen Hearne is pulling outdated nonfiction books from the shelves. She is showing one teacher how to track down primary-source documents from the Vietnam War and helping a group of other teachers design a project that uses folk tales to draw students into cross-cultural comparisons.

With the common standards on her doorstep, Ms. Hearne has a lot to do. Her library at Wren Middle School in Piedmont, S.C., is a nerve center in her school’s work to arm both teachers and students for a focus on new kinds of study. She’s working to build not only students’ skills in writing, reading, research, and analysis, but also teachers’ skills in teaching them. She and other librarians say they view the common core, with its emphasis on explanation, complex text, and cross-disciplinary synthesis, as an unprecedented opportunity for them to really strut their stuff.

Like most school librarians, Ms. Hearne has been trained both as a teacher and a librarian, a combination she thinks is perfectly suited to helping students and teachers as the Common Core State Standards presses them into inquiry-based modes of learning and teaching. She helps them find a range of reading materials in printed or online form and collaborates to develop challenging cross-disciplinary projects. And like colleagues around the country, Ms. Hearne also plays important instructional roles often unrecognized by the public: as co-instructor alongside classroom teachers, and as professional-development provider for those teachers.

“The common standards are the best opportunity we’ve had to take an instructional-leadership role in the schools and really to support every classroom teacher substantively,” said Barbara Stripling, the president-elect of the American Library Association, and a professor of practice in library science at Syracuse University. (Read more.)

In a recent survey, William Schmidt, a University Distinguished Professor of education at Michigan State University, found some good news and bad news for supporters of the Common Core State Standards. The good news was that the vast majority of teachers have read the Standards and nearly all like them. The bad news was that about 80 percent of mathematics teachers said the Standards were “pretty much the same” as their current state standards.

Those teachers might want to take a closer look. While the Common Core State Standards share many features and concepts with existing standards, the new standards also represent a substantial departure from current practice in a number of respects. Here are nine important differences: <Find out what those nine areas are.>